I played as the siren in both games on my first time through . I don't remember much of Lilith but I do remember Maya becoming RIDICULOUSLY powerful . I'm playing through 2 now with my friend and she uses Maya and that power has saved us more times than I can count.. Axton would be up there for sure if the shield on his turret actually lasted instead of being taken down so damn easy ..it feels almost useless to me ..I throw it down to create some breathing room for us and it gets taken out in a few seconds..
Lilith is just straight up overpowered, mathematically speaking. With the proper elemental loadout she can melt anything.
Brick is fun because you get to punch enemies so hard they explode.
Gaige... Screw the robot, her anarchy stacking system is too good. Max that shit out and you'll be blowing dudes away left and right, as and when you're able to actually hit them thanks to the accuracy loss.
Krieg is probably my favourite of the bunch because his mechanics encourage you to play like a crazy person. Yell at your friends to shoot you below a certain health threshold, then pop his super giant mutant form and tear everything up with a buzz axe rampage. Glorious.
(Also a neat touch is that his one-liners have a 'voice in your head' component that can only be heard client-side while playing with other people.)
Well I mean technically speaking Lilith was goddamn OP in BL1 (which I’m pretty sure Is why they treat her like a goddess in BL2) and in BL2 my vote goes for Zero and Axton. Because I like playing as them.